On the first day at a new job, your manager will most likely walk you to your desk, give you a refresher on the job description, and make sure you have all the necessary tools to be a productive employee. But there are a few aspects of a new job that aren’t quite as transparent. Outside of the human resources department, there isn’t a “company culture” handbook that comes with your new laptop and workstation.

“Most organizations don’t explain the cultural rules to newcomers, and new hires are so focused on the job and the new boss that they overlook the rules’ profound influence,” write authors Allan H. Church and Jay A. Conger of Harvard Business Review. “Yet understanding them plays a big role in your initial success. Being cognizant of not just what your colleagues do but how they work matters if you want to be effective and be perceived well.”

Below, Church and Conger outline two important dimensions of company culture that require your attention to successfully navigate a new job.

Relationships and Communication

Every company has its own unique approach to socializing and communicating for work purposes, and informal “startup culture” has thrown another wrench into this already complex dynamic. “In some organizations, the only way to influence others is by spending time with them in person. In others, emailing, texting, and video conferencing are preferred over in-person meetings,” explains Church and Conger. “Observe where and how your colleagues get work done and make decisions. Are people friendly and open to meeting with you?

Or do they appear to be nice but repeatedly cancel meet-and-greets?”

Similarly, communication can go one of two ways: formal or informal. “When you start a new job, look at how people tend to communicate with one another,” they suggest. “Is it through formal channels, like meetings that are always set in advance, and to which everyone comes well prepared? Or do individuals more often communicate spontaneously with little or no documentation?” All of these aspects influence how decisions get made, who the key players are, and how the company operates as a whole.

The Decision-Making Process

Each of these approaches to relationships and communication gives way to a unique decision-making process. In short, some tend to make real-time decisions in important, formal meetings while others finalize decisions offline, such as by the coffee station, in the hallway, or over lunch.

“If you see people agreeing to some set of actions in a meeting and then notice that other things happen afterward, that suggests there are strong informal decision-making mechanisms at play that you’ll need to uncover,” Church and Conger explain. “For example, a decision to invest in a new product might ultimately rest in the hands of two pivotal individuals—even when there is an entire senior leadership team reviewing the decision.” In that situation, they’d advise you to “meet with these two key leaders far in advance of any formal meetings and convince them of your point of view.”

In short, pay attention to what’s happening around you, and don’t be surprised if your manager takes notice.